Nationwide and NatWest both said they have fixed separate IT hitches which caused more financial chaos for customers this week.

The problems left nearly three-quarters of a million customers of Britain's biggest building society, Nationwide, out of pocket after debit card payments were taken from their accounts twice.

Nationwide said it has corrected the mistakes overnight and has promised to reimburse anyone who has incurred extra charges as a direct result.

In another blow to customers, NatWest, which is rebuilding its reputation after an IT meltdown last month, saw its online service freeze yesterday, leaving customers unable to access accounts.

Jenny Groves, divisional director for customer experience at Nationwide, said yesterday: “We are pleased to confirm that all debit card transactions processed twice have now been corrected. We wish to apologise to those customers affected.”

NatWest confirmed last night that its online banking and debit transactions had returned to normal.